Joseph R. Biden Jr.’s lifetime in the Senate and his reputation as an honest broker is paying off in a big way for the vice president as he watches his stock rise after successfully negotiating a deal to avert the fiscal cliff.

When President Barack Obama, Speaker John A. Boehner, R-Ohio, and Senate Majority Leader Harry Reid, D-Nev., all stepped away from talks in the final days of 2012, Senate Minority Leader Mitch McConnell made a last-ditch phone call to his old Senate colleague.

“The vice president and I have worked together on solutions before, and I believe we can again,” the Kentucky Republican said Dec. 30.

The same duo worked in secret on a deal that ultimately extended the George W. Bush-era tax rates for two years back in 2010.

That level of trust — lacking among the other leaders involved in the fiscal cliff deal — makes Biden the likely go-to negotiator for both the White House and congressional Republicans as they approach the March deadline to pass another debt limit hike.

Former Sen. Ted Kaufman, D-Del., who worked for Biden in the Senate, said that McConnell and the vice president never worked very closely together when they were both senators, given that they did not serve on the same committees.

But Kaufman said he thinks that McConnell relied in part on Biden’s reputation as “a guy who will never embarrass you.”

Kaufman noted that you do not see Biden cited in books after the fact highlighting times he may have scored legislative victories against the likes of legendary Senate Republicans Strom Thurmond of South Carolina and Jesse Helms of North Carolina, with whom he frequently had to reach agreement on the Judiciary and Foreign Relations committees.

His experience on the Judiciary panel — particularly on the 1994 crime bill — should serve Biden well on another big project: coming up with a way forward on gun control in the aftermath of last month’s tragic shooting at a Newtown, Conn., elementary school.

“He doesn’t have to go back and learn,” about gun violence issues, Kaufman said. “It’s a matter of sitting down and figuring out what is the art of the possible.”

Once the deal with McConnell was at hand on New Year’s Eve, the White House dispatched Biden to the Capitol to sell the package to House and Senate Democrats.

“Vice President Biden, he was very persuasive, but he did not have to do that much convincing,” New York Sen. Charles E. Schumer said after emerging from their Dec. 31 meeting.

The sentiment was much the same the next day, when a boisterous Biden could be heard from outside the House Democrats’ meeting room in the Capitol Visitor Center.

“He can probably say things that people don’t particularly like and pull people in even after saying them,” Rep. Emanuel Cleaver II, D-Mo., said after noting that many members had concerns about the substance of the agreement.

Biden’s public persona is of a famously loquacious and gaffe-prone politician, but Kaufman noted his record of deal making. Kaufman said Biden was someone fellow senators went to when they needed to find “people who really, really get things done,” even when the public spotlight shone somewhere else.